U.S. patent number 5,770,296 [Application Number 08/689,180] was granted by the patent office on 1998-06-23 for adhesive device.
This patent grant is currently assigned to Senco Products, Inc.. Invention is credited to David J. Lococo, Vladimir Pilic, Anthony T. Racca, David L. Remerowski, Duane C. Shomler.
United States Patent |
5,770,296 |
Remerowski , et al. |
June 23, 1998 |
Adhesive device
Abstract
An adhesive device, featuring a target element, absorptive of
electromagnetic waves, contiguous with a heat-activatable adhesive
material, shaped into an article having a mathematically smooth
perimeter, will facilitate a quick, neat, easy and secure assembly
of associated component pieces or manufactured articles. Exposing
the device to electromagnetic waves will produce heat energy which
will activate the adhesive material and result in the bonding of
the associated component pieces. This adhesive device is
particularly beneficial when used within or between pieces to be
assembled that are substantially transparent to electromagnetic
waves.
Inventors: |
Remerowski; David L.
(Cincinnati, OH), Shomler; Duane C. (Cincinnati, OH),
Racca; Anthony T. (Cincinnati, OH), Lococo; David J.
(Cincinnati, OH), Pilic; Vladimir (Smithtown, NY) |
Assignee: |
Senco Products, Inc.
(Cincinnati, OH)
|
Family
ID: |
24767367 |
Appl.
No.: |
08/689,180 |
Filed: |
August 5, 1996 |
Current U.S.
Class: |
428/80; 428/345;
428/41.1; 428/344; 428/42.1; 428/40.1; 428/913; 219/633; 219/634;
428/347 |
Current CPC
Class: |
C09J
5/06 (20130101); B29C 65/3636 (20130101); B29C
65/364 (20130101); B29C 65/3644 (20130101); B29C
66/246 (20130101); Y10T 428/1443 (20150115); Y10T
428/1486 (20150115); B29C 65/3684 (20130101); Y10S
428/913 (20130101); Y10T 428/14 (20150115); Y10T
428/2804 (20150115); Y10T 428/2817 (20150115); Y10T
428/2809 (20150115); B29C 65/3676 (20130101) |
Current International
Class: |
C09J
5/06 (20060101); B29C 65/36 (20060101); B29C
65/34 (20060101); B32B 003/02 () |
Field of
Search: |
;428/40.1,40.9,41.1,42.1,344,345,347,354,913,200,80
;219/633,634 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Ahmad; Nasser
Attorney, Agent or Firm: Litzinger; Jerrold J.
Claims
What is claimed is:
1. An adhesive device for the adhesive assembly of associated
components which comprises:
a target element having an upper surface and a lower surface,
composed of metal foil having a continuous surface which has a
mathematically smooth perimeter essentially defining a closed
curve, and a heat-activatable adhesive material which completely
covers both surfaces of said foil, said target element being
absorbent of electromagnetic waves, which are convertible to heat
energy to activate said adhesive material.
2. The device according to claim 1, wherein the perimeter
essentially defines a circle.
3. The device according to claim 1 wherein the perimeter
essentially defines an ellipse.
4. The device according to claim 1 wherein said foil is
manufactured from a metallic material taken from a group consisting
of aluminum, copper, and steel.
5. The device according to claim 1 wherein said heat-activatable
adhesive material is a hot-melt adhesive.
6. The device according to claim 1 wherein said foil is
manufactured from a semi-metallic material taken from a group
consisting of carbon and silicon.
7. The device according to claim 1, wherein said heat-activatable
adhesive material is a heat-activated curing adhesive.
Description
BACKGROUND OF THE INVENTION
1. Field of The Invention
The disclosed invention relates generally to an adhesive device
useful in facilitating the assembly of associated parts or
components of a manufactured or constructed product. The device
essentially comprises a target element contiguous with a
heat-activatable adhesive material and configured into a shape
having a mathematical smooth perimeter to obtain a more reliable
and secure bonding of the assembled pieces.
2. Description of The Prior Art
U.S. Pat. No. 3,574,031 to Heller et al. describes a method and
material for welding thermoplastic bodies by using a susceptor
sealant between the bodies to be joined. The susceptor sealant is
characterized by having particles, heatable by induction,
dielectric or radiant energy, dispersed in a thermoplastic carrier
compatible with the thermoplastic sheets to be welded. The welding
of the thermoplastic sheets is effected by applying and exposing
the susceptor sealant to heat energy, softening the carrier
material and joining all thermoplastic materials.
U.S. Pat. No. 3,996,402 to Sindt relates to the assembly of sheet
materials by the use of angular fastening devices utilizing an
foraminous sheet of eddy current-conducting material sandwiched
between coatings of hot-melt glue. An induction heating system is
activated causing eddy current heating in the EC-conducting
material with consequent melting of the hot-melt glue thus
resulting in fusion and, ultimately, bonding of the sheet materials
in accordance with the desired construction.
U.S. Pat. No. 5,500,511 to Hansen et al. describes an induction
welding technique using a susceptor, which in this instance is a
thin, perforated metal foil, embedded in an adhesive, placed
between the plies or layers of an assembly. Not surprisingly,
Hansen et al., prior to making their invention, experienced
difficulty in obtaining uniform heating at the weld sites on their
composite materials. According to their '511 patent, they've solved
their problem by fashioning the susceptor into a diamond-shaped
mesh with double-thick edges. While the solution to the welding
problem encountered by Hansen et al. may or may not work to solve
problems presented in an adhesive bonding situation, it is
important to make note of the fact that subtle and seemingly
superficial alterations like size and shape can effect significant
improvements in product performance.
SUMMARY OF THE INVENTION
The instantly disclosed adhesive device is distinguished from, and
improves upon, the prior art by providing an adhesive device having
a target element for absorbing electromagnetic waves, contiguous
with a heat-activatable adhesive material and shaped so that the
perimeter of the device is mathematically smooth. Such a
configuration will avoid a perimeter having discontinuous lines
which disadvantageously provide points, and therefore angles, that
disrupt the flow of eddy currents in the target element and result
in areas of excessive or insufficient heating, relative to the
remainder of the perimeter, causing challenges to the integrity of
the adhesive bond. Furthermore, heretofore, when using the devices
of the prior art, there was always the risk of damaging the
associated pieces to be assembled by experiencing intensified heat
along angular aspects of the perimeter of the prior art device.
With the presently disclosed device, that risk is now greatly
diminished.
This disclosure also relates to an improved and expeditious method
for assembling and adhering associated component pieces of various
materials which, for the most part, are transparent to
electromagnetic waves. This improved method of assembly, utilizing
the disclosed device, is adaptable to automated and assembly line
procedures and in any assembly or manufacturing setting where
speed, neatness and ease of manufacture is appreciated.
BRIEF DESCRIPTION OF THE DRAWINGS
Brief Description of the Drawing:
FIG. 1 is a top view of a circular-shaped adhesive device in
partial section.
FIG. 2 is a cross sectional view of FIG. 3 along line A--A
depicting the device being activated between associated pieces.
FIG. 3 is a top view of the adhesive device "hidden" under or
within a material transparent to electromagnetic waves.
FIG. 4 is a cross section of the adhesive device of FIG. 1 taken
along the line B--B.
FIG. 5a is a top view of an adhesive device having a circular
perimeter with shading to depict a third dimensional waffling or
corrugation effect.
FIG. 5b is a top view of an adhesive device having a circular
perimeter and a plurality of internal openings also having
mathematically smooth perimeters.
FIG. 5c is a cross section of the adhesive device of FIG. 5a taken
along line C--C.
FIG. 5d is a cross section of the adhesive device of FIG. 5b taken
along line D--D.
FIGS. 6a, 6b and 6c are top views of comparative depictions of
adhesive devices from the prior art demonstrating perimeters with
external and internal angles.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The disclosed adhesive device 10 has been designed to be a fast,
safe, neat and economical alternative to traditional fastening
devices such as brads, staples, tacks and nails for joining, in a
secure relationship, the components of the construction and
furniture industries. The disclosed adhesive device is simply, yet
essentially, constructed from a target element 11 contiguous with a
solid, heat-activatable adhesive material, which material
completely coats both sides of target element 11, as can be clearly
seen in FIGS. 1 and 4, 12. The target element must, for the most
part, be fashioned from materials or substances that are not
transparent to electromagnetic waves. Indeed, the target element
will necessarily be constructed of a composition that will absorb
electromagnetic waves. Once absorbed by the target element, these
waves will produce magnetic hysteresis and eddy currents resulting
in heat energy which will melt or activate the contiguous adhesive
material.
Typically, the target element will be fashioned from metallic
materials such as steel, aluminum, copper, nickel or amalgams
thereof which have proven utility and are readily available;
although, some semi-metallic materials such as carbon and silicon
are also known to be suitable for the absorption of electromagnetic
waves.
The target element can assume any form or shape consistent with the
overall configuration of the adhesive device. Frequently, the
target element will be presented as a metallic foil, mesh or strip,
but it could just as easily assume the shape of a bead or granule;
and, in some instances, it will be more effective to present the
target element in the form of a fiber, chip or flake of an
electromagnetic absorbable material. The point to be made is that
the target element need only be fashioned from a material
reasonably impervious to, and absorptive of, electromagnetic
waves.
In use, the adhesive device 10 needs to be situated within or
between the associated pieces 14 of items to be adhesively joined.
Typically, the associated pieces will be wood, plastic, ceramic,
fiber board or any of a variety of composite materials. As a
practical matter, of course, the associated pieces need to be
transparent to electromagnetic waves. Some materials will be more
transparent than others, and empirical adjustments can and will be
made to modulate the quantity and intensity of electromagnetic wave
energy needed to optimally activate the adhesive material 12.
In most instances, it will be sufficient for the adhesive device 10
simply to be placed between the pieces to be assembled. In other
construction or assembly situations, it will be necessary to make
some arrangements or take additional steps to make sure the
adhesive device 10 remains in place prior to activation. Such an
additional step need be little more than introducing an additional
attachment element such as a small pressure sensitive adhesive area
on the surface of the device 10. Simpler means for positioning the
device prior to activation might entail tacking, stapling, spiking
or even slotting the associated pieces to make sure the adhesive
device is situated and activated in the most effective and,
therefore, most desirable location. But these measures, of course,
would be optional procedures and in no way essential to the
performance of the device in its broadest typical and routine
applications.
When desirably situated within or between the associated pieces to
be joined or assembled, the device 10 is ready to be exposed to
electromagnetic waves 16, produced by and emanating from a
generator 15 powered by a source of alternating electric current.
The generator can be held in a fixed position for assembly-line
production or designed to be manipulated so as to quickly and
easily pass over, around or near the strategically "hidden" device
while emitting electromagnetic waves which will penetrate the
"transparent" associated pieces, be absorbed by the target element
11, be converted to heat energy, activate the adhesive material
resulting in a bonded relationship between the associated
pieces.
To elaborate, somewhat, heat is produced in the conductive target
element by two mechanisms: eddy current resistive heating and
magnetic hysteresis. Eddy current resistive heating applies to all
conductive materials and is produced in the target element by the
electromagnetic waves emanating from the generator. The heat
resulting from magnetic hysteresis is observed only in magnetic
materials. As the electromagnetic field produced by the generator
reverses polarity, the magnetized atoms or molecules in the target
element also reverse. There is an energy loss in this reversal
which is analogous to friction: This energy loss is magnetic
hysteresis. The "lost" energy is quickly converted to heat and
conducted by the target material to the contiguous, and frequently
enveloping, heat-activatable adhesive material to initiate
adhesion.
When heated to the necessary temperature, the adhesive material
will liquefy or become heat-activated, attach itself to the
adjacent associated parts, and, on cooling, create an adhesive
relationship between the associated parts.
Two adhesion mechanisms, hot-melt and heat-activated cure, are
proposed for use with the disclosed device. Both mechanisms are
initiated by heat emanating from the target element. Hot-melt
adhesives are solid at ambient temperatures, but melt or liquefy
when the temperature is elevated by, for instance, heat
accumulating in the target element. The melted adhesive "wets" the
adherends and, in the case of porous or fibrous adherends,
penetrates the surface of the pieces to be bonded. As the adhesive
cools, the adherends and adhesive are bonded by the electrostatic
attraction of polar molecular groups. In the case of porous or
fibrous adherends, mechanical interlocking can contribute to bond
strength. Note that for the hot-melt mechanism, the bonding is
reversible. Thus by repeating the induction heating procedure, the
bond can be undone and the adherends separated. The ability to
reverse the adhesion and separate assembled pieces is not a trivial
attribute. In addition to the obvious advantage of being able to
reassemble or repair misaligned pieces, it is also desirable to be
able to disassemble manufactured articles to facilitate
serviceability and repair. And, when working with associated pieces
of different materials, it will frequently be beneficial to
disassociate assembled pieces to facilitate recycling.
Heat-activated curing adhesives are also solid and easy to
manipulate at ambient temperatures, but when the adhesive
temperature is elevated by, for example, the heat emanating from
the target element, a chemical reaction is initiated. This reaction
involves a cure or crosslinked bonding either within the adhesive
or between the adherends. Such bonds are typically irreversible.
Frequently, a heat-activated curing adhesive bond will demonstrate
an electrostatic attraction between the adhesive and the adherends
and a crosslinked bond within itself
As previously mentioned, the shape or perimeter of the disclosed
adhesive device is also important to effect optimal bonding. It has
been experimentally determined that the adhesive device must have a
mathematically smooth perimeter, which could define either a planar
or three dimensional device having height or thickness to more
effectively accommodate a particular use. This smooth perimeter
could also more commonly be characterized and defined as a simple
closed curve without angles. Geometrically, a simple curve does not
cross itself, and a closed curve, understandably, is one wherein
the ends of the curve are joined. Mathematically, it would be
appropriate to define the perimeter of the disclosed device as a
continuous line having a continuous derivative. A line with a
continuous derivative is one with no discontinuity or angles.
Because it is desirable, and necessary if the most secure bond
possible is to be obtained, to achieve bonding along the entire
length of the perimeter of the device, it is necessary that there
be no angular discontinuity in the perimeter. Experimental studies
have demonstrated that departures from a mathematically smooth
perimeter will result in adhesive weakness and bond failure. For
instance, in FIG. 6a a heart-shaped adhesive device is depicted
having internal 20 and external 21 angles in the perimeter.
Experimentation has shown that the internal angle segment becomes
too hot during exposure to electromagnetic radiation and the
external angle segment demonstrates less than satisfactory adhesion
because the segment appears to be inadequately "heated" by the
amount of radiation suitable for the mathematically smooth segments
of the device. Consequently, it is an essential and distinguishing
feature of the disclosed adhesive device that there be no definable
angles in the perimeter.
It is further theorized, and experimentally substantiated, that an
angular perimeter will introduce points of stress, and ultimate
bond failure, that simply are not seen or experienced in pieces and
products assembled with the adhesive device described herein.
Furthermore, it is envisioned that the disclosed device might have
more than one perimeter. It is conceivable that in certain
applications there may be an opportunity to conserve material
and/or more aptly meet specific requirements and thereby introduce
a hole or holes in the interior of the disclosed device. In these
instances it is expected that the requirements defining the
external perimeter will also apply to these interior
perimeter(s).
Commercial applications of the disclosed adhesive device are
legion. Immediate needs for the disclosed device have been
identified in the furniture industry where neat, effective and
efficient assembly methods can readily be exploited to manufacture
affordable units in a fast, effective and clean manner. Furniture
and cabinet manufacturing applications will involve, primarily, the
assembly of associated pieces of wood and plastic, both of which
are transparent to electromagnetic waves and receptive to adhesive
bonding. Other construction uses for the disclosed device include
the fabrication of lattice panels, the installation of trim molding
and fence erection. Also envisioned is the assembly of plywood,
gypsum board and combination boards to wall ceiling and floor
framing materials. In the packaging industry, there is a need to
facilitate the fast and effective construction of containers made
of wood, plastic and especially containers made of expensive
materials made from engineered fiber base materials, which could
all be readily assembled using the disclosed device.
* * * * *